Why cutting calories won’t keep the weight off

In Summary

The only people who don't seem to appreciate this are people who have never dieted. It's particularly hard for them to believe because it doesn't square with their own eating experiences.

If you are a dieter, remind yourself that you aren't weak, but that you were in an unfair fight that very few win. Change your focus to improving your health with exercise (which doesn't require weight loss), and resolve to choose a different New Year's resolution next year.

Diets do not work.

The scientific evidence is clear as can be that cutting calories simply doesn’t lead to long-term weight loss or health gains.

Most dieters have realized this by now too. And yet, here they are again, setting the same weight loss goal this year that they set last year.

The only people who don’t seem to appreciate this are people who have never dieted. It’s particularly hard for them to believe because it doesn’t square with their own eating experiences.

A New Year, new food resolution: Mindful eating

Take Nicky, for instance. She eats sensibly much of the time, with some junk food here and there, but it doesn’t really seem to affect her weight. She’s not a dieter. She is Naturally Thin Nicky, and it’s not surprising that she believes what she sees with her own eyes and feels in her own body. Nevertheless, Nicky has it wrong.

Researchers who have been studying why diets fail for a long time, have also noted the stigma that heavy people face, and witnessed the blame game that happens when dieters can’t keep the weight off.

From a scientific perspective, we understand that dieting sets up an unfair fight. But many Nickys get confused when we say dieting doesn’t work, because it doesn’t square with their own observations.

Nicky thinks she’s thin because of the way she eats, but actually, genetics play a huge role in making her thin. Nicky gets all the credit though, because people see the way she eats and they can’t see her genes.

Many heavy people wouldn’t be lean like Nicky even if they ate the same foods in the same quantities. Their bodies are able to run on fewer calories than Nicky’s, which sounds like a good thing (and would be great if you found yourself in a famine).

However, it actually means that after eating the same foods and using that energy to run the systems of their body, they have more calories left over to store as fat than Nicky does. So to actually lose weight, they have to eat less food than Nicky. And then, once they’ve been dieting a while, their metabolism changes so that they need to eat even less than that to keep losing weight.

It’s not just Nicky’s genetically given metabolism that makes her think dieting must work. Nicky, as a non-dieter, finds it really easy to ignore that bowl of Hershey’s Kisses on her co-worker’s desk. But for dieters, it’s like those Kisses are jumping up and down saying “Eat me!” Dieting causes neurological changes that make you more likely to notice food than before dieting, and once you notice it, these changes make it hard to stop thinking about it. Nicky might forget those chocolates are there, but dieters won’t.

Why so many people regain weight after dieting.

In fact, dieters like them even more than before. This is because other diet-induced neurological changes make food not only taste better, but also cause food to give a bigger rush of the reward hormone dopamine. That’s the same hormone that is released when addicts use their drug of choice.

Nicky doesn’t get that kind of rush from food.
And besides, Nicky is full from lunch. Here again, dieters face an uphill battle because dieting has also changed their hormones. Their levels of the so-called satiety hormone leptin go down, which means that now it takes even more food than before to make them feel full. They felt hungry on their diets all along, but now feel even hungrier than before. Even Nicky’s regular non-diet lunch wouldn’t make dieters full at this point.

It’s easy to see why dieters usually regain the weight they lose on their New Year’s resolution diet, and we have the following suggestions for when that happens: If you are a Nicky, remember the self-denial these dieters have subjected themselves to and how little they were eating while you treated yourself to decadent desserts. Be impressed with their efforts, and grateful that you don’t have to attempt it.

If you are a dieter, remind yourself that you aren’t weak, but that you were in an unfair fight that very few win. Change your focus to improving your health with exercise (which doesn’t require weight loss), and resolve to choose a different New Year’s resolution next year.

Traci Mann is a professor of psychology at the University of Minnesota and author of “Secrets from the Eating Lab.” She has received grants from the National Institutes of Health, NASA and the USDA. A. Janet Tomiyama is an associate professor of psychology at the University of California, Los Angeles. She receives funding from the National Science Foundation and the Robert Wood Johnson Foundation.